Bistable cholesteric liquid crystal switchable window
AssigneeKent State University
InventorsDeng-Ke Yang, Meina Yu
Life of this patent
Estimating the term…
Abstract
A bistable cholesteric liquid crystal switchable window has two stable states in the absence of an applied voltage. A first stable state is a planar state which is transparent or reflective for visible light. A second stable state is a focal conic state which is opaque for visible light. The window can be switched from the first stable state to the second stable state via a first voltage pulse and from the second stable state to the first stable state via a second voltage pulse. The first voltage pulse and the second voltage pulse may have the same frequency.
Claims20
A bistable cholesteric liquid crystal switchable window having:
- two stable states in the absence of an applied voltage;
- wherein a first stable state is a planar state which is transparent or reflective for visible light;
- wherein a second stable state is a focal conic state which is opaque for visible light;
- wherein the bistable window can be switched from the first stable state to the second stable state by a first voltage pulse;
- wherein the bistable window can be switched from the second stable state to the first stable state by a second voltage pulse;
- wherein the first voltage pulse has a first frequency, the second voltage pulse has a second frequency, and an absolute value of the difference between the first frequency and the second frequency is less than 2000 Hz;
- and
- wherein the first voltage pulse has a first pulse width, the second voltage pulse has a second pulse width, and the first pulse width and the second pulse width are independently within the range of about 0.1 to about 1 seconds.
A method for operating a bistable cholesteric liquid crystal switchable window comprising:
- applying a first voltage to the window;
- wherein the application of the first voltage changes the window from a first transparent or reflective state to an opaque state;
- turning off the first voltage;
- and
- applying a second voltage to the window;
- wherein the application of the second voltage changes the window from the opaque state to a second transparent or reflective state;
- wherein the first voltage and the second voltage are the same or different;
- wherein the first voltage is applied at a first frequency;
- wherein the second voltage is applied at a second frequency;
- and wherein an absolute value of the difference between the first frequency and the second frequency is less than 2000 Hz;
- and
- wherein the first voltage has a first pulse width, the second voltage has a second pulse width, and the first pulse width and the second pulse width are independently within the range of about 0.1 to about 1 seconds.
Dependencies are inferred from the claim text.